S&W Shields are tough to rack. They are small and have stiff recoil springs, just the nature of the beast. Leaving it open will not make it easier to cycle.
I have a number of customers who are experiencing difficulty due to arthritis or muscle/joint damage due to accidents or surgery. I typically point them towards a larger framed pistol like a Springfield XDs, Glock, FN, kimber, etc. The larger grip, larger slide, and weaker recoil spring helps cycle the gun easier.